Water Quality Index, Heavy Metals, and Endocrine Disruptors in the Saigon River Basin: Pollution Assessment and Correlation Analysis

The present study aims to assess surface water quality (WQI), wastewater quality (WWQI), and the presence of toxic chemicals, including metals and endocrine-disrupting compounds (EDCs), in the Saigon River basin. A total of 27 samples from nine locations in the Saigon River basin and 30 wastewater samples from 10 industrial parks were collected in 2023. In addition, Pearson correlation analysis, principal component analysis (PCA), and cluster analysis (CA) were employed to investigate the relationships and potential sources of water quality parameters, heavy metals, and EDCs in surface water and wastewater. Water Quality Index (WQI) revealed that five locations (S2, S3, S6, S7, and S9) were classified as poor (WQI: 47–50), while four locations (S1, S4, S5, and S8) exhibited moderate quality (WQI: 53–64). For wastewater, three locations (W2, W3, and W7) showed low-strength wastewater (WWQI: 36–40), four locations (W4, W6, W8, and W10) had medium-strength wastewater (WWQI: 54–74), and three locations (W1, W5, and W9) displayed high-strength wastewater (WWQI: 76–80). In addition, Pb (0.50 mg/L) and Cr (0.10 mg/L) concentrations were higher than the surface water limits set by QCVN 08:2023/BTNMT (Pb < 0.02 mg/L and Cr < 0.05 mg/L). For wastewater, Pb concentration was 0.60 mg/L, higher than the QCVN 40:2021/BTNMT limit (Pb < 0.5 mg/L). The highest amount of nonylphenol monoethoxylate (NP1EO) was found in surface water samples (179.67 ± 24.88 ng/L), while the highest amount of octylphenol (OP) was found in wastewater samples (20,000.00 ± 8509.79 ng/L). The Pearson correlation test showed a strong positive relationship in surface water between bisphenol A (BPA) and nonylphenol diethoxylate (NP2EO) (r = 0.80) and Cr and NP1EO (r = 0.99). A strong positive relationship was identified in wastewater between NP and Zn (r = 0.94) and between BPA and Cr (r = 0.96). Notably, no significant correlations were found between other parameters, suggesting pollution originates from multiple point sources related to industrialization and urbanization activities in the Saigon River basin. The PCA and CA results corroborated the correlation analysis, identifying human waste discharge as the primary contributor to pollution. Therefore, the study results highlight the urgent need for comprehensive water quality monitoring strategies, particularly near industrial and residential areas, and to develop and enforce stricter wastewater discharge regulations to mitigate environmental pollution.